Method of cross-rolling



March 20, 1934. s. E. DIESCHER METHOD OF CROSS ROLLING Filed Sept. 2,1932 /m g Q pieces introduced between them) Fatented at 20, 1934 PATENTOFFICE 1,951,348 METHOD OF CROSS-ROLLING Samuel E.

Diescher Tube Diescher, Pittsburgh, Pa, assignor to Mills, Inc.,Pittsburgh, Pa, a

corporation of Delaware Application September 2. 1932, Serial No.631,510

SGlaims.

My invention pertains to a method of applying to work-pieces thepressure treatment of cross-rolls (which term is intended throughoutthis application to include other helically acting rotating members forapplying pressure to work- ,--such treatment as occurs, for example,when billets are pierced, pierced billets or other tubes are elongatedand reduced in wall thickness, tubes are reduced in diameter, tubes orbars are straightened, etc., by the action of cross-rolls.

According to certain prior inventions which I have made, discs (or,sometimes, a single disc) are mounted in the space between thecross-rolls for engagement at their peripheries with the work-piece. Thediscs serve to guide the workpiece, and/or to confine the metal of theworkpiece as the latter rotates from contact with one cross-roll tocontact with the other, as well as to perform other functions whichdepend, to a certain extent, upon the character of work being performedby the crossrolls. The frictional resistance which the discs exertagainst rotation of the work-piece, is reduced by rotating the discs inthe direction of the progression of the work-piece through thecross-rolls at a speed in excess of that of such progression.

In cross-roll mills employing discs of the character to which referencehas just been made, it is often desirable to change the distanceseparating the discs, or, ii only one disc is used, to change thedistance between the periphery of the disc and what may be termed theaxis of the throat of the cross-rolls. For example, supposing a tubularwork-piece to have been elongated, to produc and wall thickness, at agiven setting of the cross-rolls and guide discs,it would be necessaryto separate the discs more widely if it were desired to obtain, with thesame mandrel and the same setting of the cross-rolls, a tube of the samewall thickness but greater diameter. Similar occasions for varying thedistance separating the discs occur in other uses of cross-roll millsemploying such discs.

The above-mentioned change of the distance separating the discs has,prior to this invention, presented a difficulty which often could onlybe overcome by removing the discs from the machine and substitutingothers of a difierent width. The difflculty arose from the fact that itwas often considered necessary to construct and arrange the discs sothat they presented peripheral areas, for engagement by the work-piece,which covered substantially as much of the space existing between thecross-rolls as possible. This involved that the edges of the discs cameinto close proximity with the adjacent cross-rolls, and, since the spacebetween the cross-rolls narrows as the axis of the throat is neared, thediscs could 60 not be brought more closely together without coming intocontact with the surfaces of the cross-rolls. On the other hand, thediscs could not be moved further apart without leaving undesirablespaces between their edges and the surfaces of the cross-rolls.

It is the primary object of the present invention to provide a method ofcross-rolling with the use of rotating discs of the above-mentionedcharacter, in which the foregoing difflculty will be obviated. I obtainthis object by subjecting the work-piece to the engagement-for guiding,confining or other purposes,of the rotating discs at areas which, in thecase of each disc, are nearer to one cross-roll than the other. If adisc is made to engage the work-piece at an area closer to thecross-roll which moves the metal of the workpiece towards such disc thanto the other crossroll, I find that the disc will perform its functionsatisfactorily without engaging the work-piece in the region close tosuch other cross-roll,--that is, the cross-roll towards which the metalof the work-piece moves from the disc. By this mode of guiding,confining, or otherwise operating on the work-piece, I am enabled toleave space, in 85 the case of each disc, between such disc and thatcross-roll towards which metal moves from the disc. This in turn allowsthe discs to be moved towards and from each other through materialdistances, while the edge of each disc canahy being o 'm ipofg cam m mmeved transversely stillpbe lrept' in close proximity with thecross-roll which moves the metal of the work-piece towards such disc.

The practice of my improved method will be more readily understood fromthe accompanying drawing, in which,

Fig. l is an end view, of a schematic nature, of a cross-roll millemploying discs of the character mentioned above, the mill being viewedin the direction of the feed of the work-piece therethrough;

Fig. 2 is a section on and Figs. 3 and 4. are fragmentary views, similarto Fig. 1, illustrating the manner of moving the discs for differentworking conditions.

An operation of elongating and reducing the wall thickness of a tubularblank, to produce a seamless tube, has been selected for illustration.The blank A, upon a mandrel B, is fed to a pair 110 the line lI-1I ofFig. l;

or crose=rolls 12, 13, between which are mounted a pair of discs, 1e,15, which engage the workpiece one on each side thereoi. These discs arerotated in the direction of the arrows (Fig. 2), that is, in thedirection 05; the progression of the work-piece through the cross-rolls,at a peripheral speed in excess of the longitudinal speed of suchprogression of the work-piece. The portion of the work-piece which is,at the moment, in the throat of the cross-rolls is designated A and theportion thereof which has been elongated is designated A.

From the arrows on Fig. 1, it will be seen that the cross-roll 12 ismoving the metal of the workpiece towards the disc 14, while thecross-roll 13 is moving the metal towards the disc 15. In the practiceof my invention, I cause the guiding, confining or other engaging actionof each disc to occur to a greater extent on the side of its peripheryadjacent the cross-roll which is moving the metal towards it than on theother side, that is, in the case of the disc 14, more on the side of itsperiphery adjacent the cross-roll 12 than on the side adjacent thecross-roll 13. While allowing one edge of each disc to be placed inclose proximity with the cross-roll which is moving metal towards thedisc, this permits a considerable space to be left between the otheredge of such disc and the other cross-roll, thereby pro vidlng room formovement of the discs in a transverse direction as an incident to amovement towards each other.

The periphery of each disc is of a curved transverse contour so chosenthat the metal coming to the disc from the adjacent cross-roll will beproperly deflected and directed towards the cross-roll towards which themetal moves from the disc. Such contour may conveniently, though notnecessarily, be that of the arc of a circle, of a diameter larger thanthat of the largest article that will be produced, which has its centerbeyond a plane central of, and parallel with, the disc. Considering adisc as positioned so that its periphery is spaced from the axis of thethroat of the cross-rolls by a distance somewhat larger than thegreatest distance that will be required (for that disc) in practice, andas being placed with one edge of its periphery in close proximity withone of the cross-rolls, as described above, the contour 01' theperiphery of such disc may be that of a circle drawn about the axis ofthe throat of the cross-rolls as a center.

The mahrnerhrwhich the work-piece is engaged by the discs, and thedifferent positioning of the discs which is thereby made possible, willbe readily understood from Figs. 3 and 4. Fig. 3 shows the cross-rollsas set, with respect to the mandrel B for producing an elongated tube ofa given wall thickness. The diameter of the elongated tube will becontrolled by the position of the discs 14, 15, which are shown aswidely separated, so as to produce a tube of relatively large diameter.The separation of the discs is somewhat exaggerated, however, in thefigure for ease of comparison with Fig. 4. Taking, for instance, thedisc 14, it will be noted that this disc is engaging the work-piece atan area nearer to the cross-roll 12 than to the cross-roll 13, that amaterial space is left between the edge of the disc and the cross-roll13, and that the edge 14a of the disc is in close proximity to thecross-roll l2,-so that the disc immediately intercepts and deflects themetal as it moves from the crossroll 12, and no space exists betweensuch crossroll and the edge of the disc into which the metal might tendto flow. The space between the disc and the cross-roll 13 provides roomfor the disc to be moved further in towards the axis of the throat ofthe cross-rolls, permitting the disc to be moved transversely towardsthe cross-roll 12 (so as to avoid contact of its edge 14a with thecross-roll 12 when the disc is thus moved further in towards the axis ofthe cross-roll throat). Fig. 4 shows the same setting of the cross-rollswith respect to the mandrel B, giving a tube of the same wall thicknessas before. However, the discs are placed more closely together, toproduce a tube of smaller diameter. To bring the discs into the closerposition, they are moved so as to approach each other and alsotransversely as is indicated by the dotted lines a continuing the edge14a of the disc 14 in the two figures, and the dotted lines b continuingthe edge 15a of the disc 15.

I claim:

1. The method of treating work-pieces by means of cross-rolls, whichincludes applying to the work-piece, between the cross-rolls, at an areanearer to the cross-roll which rotates the workpiece toward the pressuremember than to the other cross-roll, the engaging pressure of a membermoving in the direction of the longitudinal progression 01 thework-piece through the crossrolls at a speed greater than that of suchprogression.

2. The method of treating work-pieces which includes subjecting awork-piece to the action of a plurality of cross-rolls andsimultaneously applying to the work-piece, intermediate the cross-rolls,the engaging pressure of a member having its engaging surface disposednearer to the cross-roll which rotates the work-piece toward thepressure member than to the other cross-roll, and moving in thedirection of the longitudinal progression of the work-piece through thecross-rolls at a speed greater than that of such progression.

3. The method of treating work-pieces which includes subjectinga-work-piecetatlfaction of a plurality of cross-rolls and simultaneouslySAMUEL E. DIESCHER.

